DESCRIPTION (Verbatim From Applicant): In order to expand the clinical utility of bone replacement materials, we are proposing to develop a biodegradable bone graft extender with inductive capacity. Inductive biodegradable extenders would be useful in situations where autografts are preferable, yet the patients own bone stocks are insufficient. This SBIR Phase I project will determine the feasibility of enhancing the regeneration of skeletal tissues with an extender fashioned from the biopolymer poly(propylene glycol-co-fumaric acid) (PPF). This unsaturated polymer can be crosslinked in the presence of effervescent agents to create an osteoconductive network that can be immediately mixed with autograft prior to defect filling. In Phase I we will seek to develop polymer/bone combinations that demonstrate in vitro and in vivo durability over time, while supporting bone formation equivalent to traditional autologous bone grafting. Phase II would then address research objectives directed towards resolution of the clinical dilemma where autologous bone graft is recognized as the preferable "gold standard," but may not be available in sufficient quantities. This composite could have biological properties that are superior to the cortico-cancellous allogeneic bone chips routinely used in this situation. Osteoinductive autograft material used in conjunction with a highly osteoconductive, yet resorbable, scaffold would be attractive for both induction and expansion of new bone formation. PROPOSED COMMERCIAL APPLICATION: Bone grafts are used in over 425,000 musculoskeletal operations annually. Overall, 80% of the bone grafts are used in orthopaedic and spine surgery. Autografts are the preferred grafting material, but sometimes the patient's own bone stocks are deficient. It is estimated that synthetic bone replacement materials are used in only 25,000 - 35,000 of clinical grafting procedures because they are primarily only osteoconductive. If autogenous grafts could be easily extended via a resorbable osteoconductive material, market acceptance would follow.